Optical head device
CA 2000416 A1 · Owner: Tatezono, Fumio · Inventors: Tatezono, Fumio; Kume, Minoru; Yamamoto, Shigeaki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An optical head device for projecting a light beam on a recording medium to record data thereon or reproduce the recorded data comprises an optical system for forming a beam spot of a specified diameter on the surface of the recording medium, and a transparent contact member disposed at a light emanating portion of the system for the recording medium to come into direct sliding contact therewith. Accordingly when the contact, member moves relative to the recording medium the dust, adhering to the surface of medium is removed by the contact member to assure a recording or reproduction operation free of errors.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed October 11, 1989. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 11, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 11, 2011.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.